Appeal 6000220

The appeal is allowed and planning permission is granted for rear dormer loft conversion with roof terrace and roof lights to front roof slope at [site address] , Twickenham [postcode] in accordance with the terms of application, Ref 24/3138/FUL, subject to the following conditions:

The development hereby permitted shall begin not later than three years from the date of this decision.

The development hereby permitted shall be carried out in accordance with drawing nos: Site Location Plan; 014_02000_P2; 014_02001_P2; 014_02100_P2; 014_02101_P2; and 014_02200_P2.

The external materials of the extension hereby permitted shall match those used in the existing dwelling and shall be retained as such thereafter.

The development hereby permitted shall be carried out in accordance with the provisions of the [name] and shall be retained as such thereafter.

Following the submission of the appeal, the Richmond upon Thames Local Plan 2024 - 2039 (RLP) was adopted in October 2025. The main parties were given the opportunity to comment on the change in policy context and where they have been submitted, these comments have been taken into consideration.

The main issues relevant to this appeal are the effect of the proposal on the character and appearance of the area; and the effect of the proposed terrace on the living conditions of nearby occupiers with regard to noise and disturbance.

The appeal property is an end-terrace, two-storey dwelling that has been converted into flats. It is constructed in buff-coloured London stock bricks with a gable-ended tiled roof and includes a two-storey rear outrigger with a mono-pitched roof set below the main ridge. Due to its position on a junction, both the rear elevation and outrigger are visible within two street scenes. The surrounding dwellings share a consistent scale, form, and palette of materials, which collectively contribute positively to the character of the area. While rear dormer windows are present within the wider locality, they are not a defining feature but do form part of the area’s character.

The proposed dormer would be set in from the roof edges, positioned below the ridgeline and above the eaves, generally in accordance with the [name] and External Alterations Supplementary Planning Document (SPD). Although the setback from the eaves would be limited, the dormer’s overall scale and siting would preserve the original roof profile and avoid visual dominance. The proposed windows, while slightly larger than those at first floor level, are similar in form and would not appear disproportionately large when viewed from the street. The inclusion of hanging tiles and the limited number of narrow windows would ensure the dormer would visually integrate with the rear roof slope. On balance, the minor departure from SPD guidance would not cause harm to the character and appearance of the area in this instance.

The roof terrace would be located adjacent to the dormer within the rear outrigger’s roof, recessed significantly from the eaves and positioned between two chimney stacks. This arrangement would limit its overall size and retain a substantial portion of the existing roof form. Although the glass balustrade would be visible, its transparency would allow the mono-pitched roof to remain legible, thereby avoiding significant erosion of the building’s form. The use of a brick slip finish similar to the bricks used in the host dwelling would help the terrace integrate into the building. While roof terraces are uncommon locally, for the reasons given above, the proposal would not appear incongruous or harmful in this context.

Within the wider area, rooflights within front roof slopes are not uncommon and given the limited size and number proposed the proposed rooflights would not clutter the front roof slope.

Therefore, for the reasons given above, the proposed development would not harm the character or appearance of the area and would accord with Policy 28 of the RLP. This policy expects developments, amongst other matters, to be compatible with the local character and to be of a high architectural and urban design quality.

The appeal property is situated within a predominantly residential area where some level of noise and activity from socialising is to be expected. The proposal would introduce a roof terrace that would enable socialising to occur closer to nearby first-floor rooms. However, the terrace is modest in size, inherently limiting the number of occupants at any one time. It is also set back from the eaves and oriented towards the road, generally facing away from neighbouring dwellings and gardens, except for the property on the opposite side of [address]. That property lies across the road, meaning the most likely affected rooms and garden are at a considerable distance from the proposed terrace. Given the terrace’s modest size and its recessed position, the development would not result in significant noise or disturbance to neighbouring occupiers at a level that would cause unacceptable harm to their living conditions.

Therefore, for the reasons given above, the proposed terrace would not unacceptably harm the living conditions of nearby occupiers and would comply with Policy 46 of the RLP. This expects developments, amongst other matters, to ensure that balconies do not cause unacceptable noise or disturbance to nearby occupiers.

Taking into consideration the size, location and the height of the glass balustrade and the location of the dormer window, the development would not result in harmful overlooking of the surrounding properties, above and beyond what already takes place given the close siting and intervisibility of the surrounding properties.

Based on the submitted evidence the appeal site is located in [name] 2 and is an area susceptible to groundwater flooding. However, the proposal seeks to extend an existing dwelling at roof level and would not increase the footprint of the house. Therefore, based on the information before me, the proposed development would not increase the risk of flooding elsewhere.

Each case must be assessed on its own individual merits. While there may be concerns regarding a number of matters those raised are generally addressed through different legislation. Matters relating to private interests such as land or property value, as well as other matters such as building regulations, the Party Wall Act and structural design, have little to do with the merits of the appeal and can often be addressed between the parties outside the appeals process.

Further to the statutory commencement condition a condition requiring the development to be carried out in accordance with the permitted plans is necessary in the interests of certainty. A condition requiring that the materials used are similar to those used in the dwelling is necessary in the interests of the character and appearance of the area. Although originally suggested as part of the plans condition, a separate condition requiring the development to be carried out in accordance with the provisions of the [name] is necessary in the interests of fire safety in accordance with Policy D12 of the London Plan.

The proposed development would be in accordance with the development plan, and the material considerations do not indicate that the appeal should be determined other than in accordance with it. Therefore, for the reasons given above, I conclude that the appeal should be allowed. [planning inspector] INSPECTOR